1. Field of the Invention
The present invention relates generally to a baler and, more particularly, is concerned with an improved system for counterbalancing the pickup of the baler.
2. Description of the Prior Art
The present invention provides a baler pickup counterbalancing system which constitutes an improvement over that disclosed and illustrated in U.S. Pat. No. 3,798,885 which issued Mar. 26, 1974 to Emmett F. Glass and Robert G. Young and is assigned to the same assignee as the present invention.
The prior art counterbalancing system disclosed in the aforesaid patent includes a relatively long low rate tension spring (or a pair of such springs connected in seres) disposed parallel to and above the baler pickup, a sheave rotatably supported on the baler above one end of the pickup and a cable and link assembly interconnecting the spring and the one end of the pickup. The cable is connected to one end of the spring and extends horizontally therefrom to and about the sheave and then extends downwardly to its connection with an upper end of the link. The link is pivotally connected at its lower end to the one end of the pickup such that the moment arm of the upward lifting force about the pickup pivot point will increase as the spring load decreases. In above-described system, the increasing moment arm is critical to the utilization of a low rate spring or springs in series.
While the prior art system has, in an overall sense, proven to be a satisfactory way to counterbalance the baler pickup, some disadvantages have been discovered.
One disadvantage relates to the frictional forces created between the cable and rotating sheave which tend to increase the load on the counterbalancing springs and thereby somewhat diminish their effectiveness in providing uniform floation of the pickup.
Another disadvantage is derived from the presence of these frictional forces, such being undesirable wear of the cable of sheave which shortens the useful life of these components necessitating frequent maintenance or replacement.